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Old 11-18-2007, 12:14 PM
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Quote:
Originally Posted by sicksubie View Post
OK thanks..... What about telling me about the GT4094R turbo? Can you plug that into the spread sheet?
Not at present. It is only populated with blower [supercharger] data at the moment. It can give output info for the likes of Lysholm, Autorotor, Sprintex, Eaton etc.

I'm sure it could be configured to give similar information about turbos, but you will appreciate we have been working with PD superchargers for a number of years, and we have never bothered with turbos.

There would be two different factors to account for using centrifugal pumps as opposed to the positive displacement types we have programmed in. One is, with the belt-driven centrifugal types, such as OT's, there would not be a theoretical leak-back limit, the pressures [boost] reached would not have a ceiling other than that governed by rev limits of the turbo and size.

The other difference is in charge temperature. In addition to increased temperatures of the charge caused by pumping pressure and inefficiency, the turbocharger would also add extraneous heat leaked over from the exhaust driven drive mechanism. This would be a variable that would be hard to compute accurately and might vary from one installation to the next.

Naturally, belt-driven superchargers like the Rotrex will not add this additional heat load, their charge temperatures will be dictated by pumping efficiency, which in their case is pretty damn good.

That also reminds me that any figures I have quoted you would be based on the theoretical best possible expectation if it included liquid injection or intercoolers. In practice, poor installation of the intercoolers can reduce the HP available, often by a very considerable amount.

Joe
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